Henderson 1915 review
Model Four. By 1915 the first production model began rolling off the assembly line. The 1912 model had the designation "4" after the 57ccm inline four-cylinder engine producing 6hp. The 1915 Henderson Model 4 engine produced 7 hp.
The Henderson Motorcycle Company
was sold to Excelsior owner Ignaz Schwinn In 1917, becoming Excelsior-Henderson, under the Excelsior Motor Mfg. and Supply Company of Chicago, Illinois. William G. Henderson left the Excelsior-Henderson company in 1920, starting the Ace Motorcycle company. More specs
and user manual
of Henderson 1915 you can see in next overview